Apparatus for treating fabric workpieces in sequence at a plurality of work stations

ABSTRACT

A transfer module for transferring fabric workpieces from one workstation to another along a low friction surface, including an arm swingable forward and back with friction gripping means carried by the arm and engageable with the workpieces to slide and orient the workpieces relative to a series of workstations. The arm is shown including a parallel linkage.

States Patent Inventor George F. Hawley Bogota, NJ. Appl. No. 871,326 Filed Nov. 19, 1969 Division of Ser. No. 601,768, Dec. 4, 1966, abandoned. Patented Aug. 24,1971 Assignee Ivanhoe Research Corporation New York, N.Y.

APPARATUS FOR TREATING FABRIC WORKPIECES IN SEQUENCE AT A PLURALII Y 0F WORK STATIONS "l Claims, 17 Drawing Figs.

U.S. Cl 271/54,

[51] Int.Cl B65h5/10 [50] Field ofSearch 271/54,14, 84; 198/218 [56] References Cited UNITED STATES PATENTS 1,884,947 10/1932 Winkley 271/54 2,577,084 12/1951 Laxo 271/54 Primary Examiner-Joseph Wegbreit Attorney-Bryan, Parmelee, Johnson & Bollinger ABSTRACT: A transfer module for transferring fabric workpieces from one workstation to another along a low friction surface, including an arm swingable forward and back with friction gripping means carried by the arm and engageable with the workpieces to slide and orient the workpieces relative to a series of workstations. The arm is shown including a parallel linkage.

PATENTEDAUG24 |971 l 3601.A 3923 l Y sHEU 1 nr 8 INVENTOR.

BY GEORGE F. HAWLEY BRYAN, PARMELEE, .manson a Bouman ATTORNE'YS.

PATENTEU Masami SHEET 2 UF 8 INVENTOR,

GEORGE F. HAWLEY BRYAN, PARMELEE, Jolmsou L Bouman ATTNEYS.

PATENTEUAUzdiQn 3601.393,

SHEET 3 nf 8 INVENTOR.

GEORGE F. HAWLEY BRYAN, PARMELEE, JOHNSON 6| BOLLINGER TTO/VEYS.

PATENTEDAUGMIQH I 3,601,393

snm l 0F 8 mwen/TUR. BY GEORGE F. HAwLEY BRYAN, PARMELEE, JOHNSON & BOLLINGER A TTUPNEYS Pmmmmmn 3.601.393

SHEET S UF 8 RETURN RETURN I N VENT( )R.

GEORGE F. HAWLEY BRYAN, PARMELEE, JOHNSON a BoLLmcmi ATTORNEYS.

PATENTEU Au24 |971 SHEET B UF 8 IN VENT( JR.

GEORGE F. HAWLEY BRYAN, PARMELEE, JOHNSON BOLLINGER A TTORNE YS PAIENIED Auczmsn :3.501, 393

snm 7 nr 8 INVENTUR GEORGE F. HAwLEY BRYAN.. Immun, Jonsson s acumen ATTORNEYS pmmfmumsn l 3.501.393

SHEET 8 UF 8 E 'IIE n INvrNmrL BY GEORGE F. HAWLEY BRYAN, Pmmn, Jonsson s Bouman ATTURNEYS APPARATUS FOR TREATING FABRIC WORKPIECES IN SEQUENCE AT A PLURALITY F WORK STATIONS This case is a division of Ser No. 601,768, filed Dec. 4,

1966, now abandoned.

The present invention relates to method and apparatus for treating fabric workpieces in sequence at a plurality of work stations. More particularly the invention relates to process and apparatus for automatically performing a sequence of work operations upon predetermined portions of a plurality of workpieces at a sequencel of work stations.

The present invention enables automobile or semiautomatic production systems to be set up quickly and easily for manufacturing various types and sizes of fabric goods such as clothing, headgear, footgear, home furnishings, and av the like, including subassemblies of such goods. This invention enables such production systems to have flexibility in operation so as to accommodate various sizes, styles and types of fabric workpieces with a minimal amount of changes in tooling or dies in the system.

The yinvention can be embodied in production systems for performing various sequences of work operations upon a plurality of workpieces as will be explained further below, and the villustrat-ive embodiments of the invention relate to fabric creasing and transferring for creasing an edge portion of a fabric workpiece so that the raw cut edge of the fabric is turned back against the body of the workpiece in preparation for suitable covering. One illustrative embodiment of this invention relates to a creasing and transferring process for turning back and creasing different predetermined increments of the edge of the workpiece in various work stations and adapted for handling different sizes and shapes of workpieces. ln one of its aspects this invention relates to transfer module apparatus having wide utility in the automatic processing of fabric workpieces for transferring workpieces from one work station to the next in a sequence of work stations.

In the process o f automatically performing a sequence of work operations upon a plurality of fabric workpieces, in the broad aspects thereof, each successive workpiece is registered in a known position, a predetermined work operation is performed on each successive registered workpiece at a first work station, and each workpiece in succession is transferred from the first work station to a second work station and is turned into a different angular orientation, while being controlled so as to position the workpiece in a predetermined registered relationship relative to the second work station. A further operation is performed on each of the workpieces at the second station, and the treated workpieces are delivered in succession from the second work station. 4 ln accordance with the fabric creasing embodiment of theA the process has been completed the edge remains turned back in preparation for lining or covering of the piece to form a finished part of a garment, apparel, or the like. In this process an increment of the edge is turned back and creased in a first work station, then the workpiece is transferred along the supporting surface to a subsequent work station and another increment of the edge is turned back and creased, and so forth, until the desired total portion of the edge is turned back and remains creased in readiness for further processing.

In accordance with one aspect of this invention transfer apparatus for moving the workpiece along a supporting surface from one work station to another is provided in the form of transfer modules which are conveniently adapted to be used singly or in sets for transferring the workpieces with various desired sequential movements.

Among the many advantages of the illustrative creasing process embodying the present invention are those resulting from the fact that a facility and convenience are provided for creasing the edges of various sizes and shapes of fabric workpieces and for handling a variety of shapes and sizes of such pieces.

A further advantage of the invention results from the fact that a transfer module is provided which is flexible in application and readily adapted to be embodied in various arrangements for transferring fabric workpieces in sequence from one work station to another and for changing the orientation or relationship of the workpieces by predetermined known amounts.

As used herein the term Ifabric is intended to include woven goods and also nonwoven, felted, or perforate goods having a flexibility suitable for use in clothing, headgear, footgear, and similar use, regardless of whether the material of the goods is in one layer or multiple layers and regardless of whether the goods are formed of natural material, synthetic material or blended materials, As used herein the term workpiece is intended to include individual pieces as well as subassemblies or semifinished goods including two or more pieces or components secured together.

i' The term transfer or transferring is intended to means the movement of afabric workpiece from one region to a second region, while maintaining known positional relationships for the workpiece during this movement.

In this specification and in the accompanying drawings are described and shown method and apparatus for treating a plurality of fabric workpieces in sequence at a plurality of work stations illustratively embodying the present invention, and it is to be understood that these examples are notintended to be exhaustive nor limiting of the invention. These examples are given so as to disclose the invention fully and clearly to those skilled in the art so that the reader will appreciate how this invention can be adapted in various forms, each as may be best suited for the conditions of a particular type of fabric workpiece in a particular production system.

The various objects, aspects and advantages of the present invention will be more fully understood from a consideration of the following description in conjunction with the accompanying drawings, in which:

FIG. I is a perspective view illustrating the process and ap- I paratus for performing a sequence of work operations upon predetermined portions of a plurality of workpieces at a sequence of work stations.

FIG. 2 is a partial plan view of the process and apparatus of FIG. l, the workpiece being turned into different orientations at the various work stations;

FIG. 2A is an enlargement ofa portion of FIG. 2 and showing steps in a process of creasing various predetermined increments of the edges of the workpieces in sequence;

FIG. 2B illustrates the flexibility of the process for creasing various sizes of similarly shaped workpieces;

FIG. 2C is a further embodiment-of the invention wherein the workpieces are registered at each of a plurality of work stations providingl great vflexibility in accommodating size changes;v

FIG. 3 is a plan view of one of the transfer modules of the system of FIGS. l and 2, and shown on enlarged scale with a part broken away to illustrate the structure;

FIG. 4 is a side elevational view of the transfer module of FIG. 3, as seen from the direction 4-4;

FIG. 5 is a perspective view of the module of FIGS. 3 and 4;

FIG. 6 is a partial perspective view illustrating a modified embodiment of the module of FIG. 5;

FIG. 6A illustrates successive operating positions of the apparatus of FIG. 6;

FIG. 7 is a view similar to FIG. 6 and illustrating a further modified embodiment;

FIG. 8 shows a plurality of modules in simultaneous use for transferring a large fabric workpiece;

FIGS. 9A and 9B are motion diagrams for purposes of explaining two sequences of operation;

FIGS. 10 and ll are perspective views illustrating two steps in the creasing of a curved portion of periphery of a workpiece; and

FIG. l2 is a cross-sectional view of the apparatus shown in FIGS. and l1.

In the process shown in FIGS. 1, '2, 2A, and 2C a sequence of work operations are performed upon predetermined portions of a plurality of fabric workpiece W at a sequence of work stations A, B, C and D. At each of the work stations the workpieces are oriented and registered so that the operation to be done is carried out on a different respective predetermined portion of the workpiece. In this manner a manufacturing Vsequence is accomplished by moving the workpiece through these stations.

In this illustrative example the work operations are shown as being a sequence of creasing steps, and it is to be understood by those skilled in the art that other fabric treating steps such as sewing, cementing or heat fusing can similarly be accomplshed. The various fabric workpieces W are transferred to the successive stations A, B, C, and D by sliding them along a low-friction work supporting Vsurface provided by the smooth top surface ofa long table 22. At each station A, B, C, and D-a different predetermined increment of the edge of the workpiece is turned back and creased. Thus, after the workpiece has been successively treated in each of the work stations, the desired total portion of the edge has become turned back and remains creased in readiness for further processing, and the creased workpieces are then combined with another workpiece V at an output station O.

The workpieces W are each initially supplied to an input registration station R and are automatically brought into a known position at this input station by registration means 21 and 23 located beneath the table 22. The known position of the workpieces is obtained by applying force impulses to the workpiece alternately directed toward edge stops 24 and 25 so as to bring the respective edge portions of the workpiece up against the stops 24 and 25 located at the input station. This registration may be accomplished by automatically placing each workpiece on the supporting surface 20 in the vicinity of the stops 24 and 25. Then registration apparatus located beneath the table 22, for example such as shown in my joint copending application Ser. No. 475,986 filed July 30, 1965, serves to impel the edge of the workpiece against the stops 24 and 25.

In order to transfer the workpieces W along the supporting surface 20, there are a plurality of transfer modules 26 located intermediate each of the stations. These transfer modules are shown more clearly in FIGS. 3, 4, and 5, to which attention is invited. These transfer modules 26 are all identical except for certain modifications in their transfer arm means 2'7, as will be explained further below, for providing various transfer motions. The arm means 27 include a pair of parallel arm members 28 each pivoted by a universal bearing 31 to a base plate 29 adapted be secured to the table 22. A bracket 30 (FIG. 4) extends up from the base 29 and holds drive means 32 in the form of an electric motor connected to a speed-reducing gear unit 33 having a vertically extending drive shaft 34 with a crank arm 36 secured thereto so that this crank 36 revolves in a horizontal plane generally parallel with the workpiece supporting surface 20.

At the outer end of his crank 36 there is a sleeve bearing 38 (FIG. 4) in which is mounted a verticallyslidable stud shaft 40, said stud shaft carrying both a cam driver element 42 and a cam follower button 43. This cam driver 42 is cylindrical and engages in a contoured slot 45 (FIG. 3) in a cam plate 46 which extends across between the pair ofarm members 28 and is pivotally connected to each of these arm members by a pair of pivot bolts 47. Thus, the arm members 28 are swung back and forth by the revolving driver 42. The cam follower element 43 is a rounded conical button on the lower end of the driver which rides against an elevator cam 44, so that a shoulder surface above the button 43 lifts or lowers the plate 46 to raise or lower the arm members 28.

The cam plate 44 is detachably secured to the base plate 29, and when it alone is used the cycle of motion produced is as shown in FIG. 9A wherein the arm means 27 is in its elevated position during the return stroke and is in its lowered position during the advancing transfer stroke, there being purely vertical travel during a dwell period at each end of the stroke.

By attaching another cam as indicated by dotted lines at 44 (FIG. 4), then the cycle of motion produced is as shown in FIG. 9B. It is to be understood that the return and advance strokes in FIG. 9B exactly retrace each other, the respective arrows being offset merely for clarity of illustration. This cycle of motion as shown in FIG. 9B is used when the fabric workpiece is being lifted during the advance stroke by a suction and friction gripper as shown in FIG. 7, as will be explained further below.

To engage and move the fabric workpiece W, friction gripping means 48 can be secured to the outer ends of the arm means 27, as shown in FIG. 4. The friction gripping means 48 include a link member 49 extending across between the arms 28 and detachably held by pivot bolts 50 with a resilient pad 51 beneath the member 49 adapted to provide a high coefficient of friction against the fabric, for example, this pad 5l is shown as sponge rubber.

Thus, the workpieces W (FIG. 4) are moved and controlled in position during movement by the differential in friction as between the low-friction supporting surface 20 engaging the lower face of the workpieces W and the high friction gripping means 48 engaging the upper face of the workpieces. In this example the low-friction surface 20 is a hard smooth polished table top forexample of hardwood, metal, or the like, it being shown here as aluminum. It is noted that the two arm members 28, base 29, and link 49 comprise a four-bar parallelogram linkage of which the base 29 is held stationary. Thus, as the arm members 28 are swung about their respective pivots 3l, the link 49 always remains parallel with its initial position. ln this manner the fabric workpiece W engaged by the frictiongripping means 48 can be transferred from one station to the next while retaining its known relative orientation.

The vertical travel as shown in FIGS. 9A and 9B at each end of the stroke assures that the workpiece is not accidentally displaced laterally at the moment of engagement or disengagement ofthe workpiece by the transfer module.

For swinging the arm means 27 as indicated by the arrow 53 and for providing a substantial dwell time period at the end of each stroke, the contoured slot 45 (FIG. 3) has a pair of end recesses 52 with opposed sidewalls adapted to straddle the revolving driver 42, and arm means 27 are swung in the advance or return stroke when the driver 42 is in a recess 52. This stroke continues as the driver 42 travels along the wall surface 54 forming a continuation of one side of the recess 52.

In the position of the driver 42 as shown in FIG. 3, the arm means 27 have reached the limit of their stroke, and the dwell period occurs as thedriver 42 moves through the angle 55 while travelling along a curved length 56 of the wall, this curve 56v being concentric about the axis of drive shaft 34. During this dwell period 55, the cam follower button 43 rides down a slope of the cam 44 to lower the friction gripper means 48 per- -pendicularly onto a fabric workpiece W. It is noted that the shoulder of the button 43 remains beneath the cam plate 46 in spite of the fact that the central portion of the slot 45 is enlarged.

In order to provide substantially vertical travel of the friction gripper pad 51, the pivots 31 are positioned close to the plane of the support surface 20, thereby assuring that the pad 5l is moving in a direction substantially perpendicular to the surface 20 at the instant when the pad 51 engages or disengages the workpiece.

In this illustrative embodiment the slot 45 is symmetrical and it includes a second curved surface 56 for providing a dwell period during elevation of the friction gripper means 48 at the limit 27', 28 of the advance stroke, as the driver 42 moves through the angle 55.

As discussed during the introduction, the contoured cut edge 60 of the workpiece is turned back against the body of the workpiece and is creased in preparation for subsequent operations, such as uniting with a suitable covering or lining,

as the case may be. This creasing process is carried out in incremental steps as illustrated most Clearly yin FIG. 2A. Predetermined increments I-l, 1 2, I-3 andiI-4 of the convtgt-:red edge 60 of the workpiece W are creased at the respecvare those resulting from the fact that the production line as shown can readily be set up to crease a different size but similarly shaped workpiece. This flexibility in set up and ability to handle different sizes of similarly shaped workpieces is illustrated `further in FIG. 2B and is advantageous in garment production lines, `because the components of different sizes of the same type of garment have similar shapes. In this process the respective curved edge portions of vdifferent size workpieces are made the same, it is the straight line segments which have different length. FIG. 2B shows larger and smaller workpieces W-l and W2 wherein the respective curved segments of the edges 60 have the same curvature but the straight line segments of the respective edges 60 are of different length. The smaller workpiece W-2 `is shown dotted merely for clarity of distinction.

By virtue of the fact that each creasing increment I-l, 1-2, I3, I4 begins and ends on a straight line segment of the curved edge 60, these creasing increments fit the respective curves and will crease the edges 60 of either workpiece W-l or`W-2.

As shown in FIG. 2A, when the workpiece is being trans-l tion being indicated by the composite arrows 61 and 62. A

workpiece W over and down onto the anvil blade 7l. The

anvil blade is withdrawn, and the crimp blade 74 presses down to complete -the crease. To give a set to the crease, the blade 74 includes heating means 82. After the crease is set, the blade 74 returns to its initial position and the workpiece is then transferred to the next station.

In order to change the production line set up, the transfer modules 26, can readily be moved into different positions by adjusting the location of the base plate 29. The length of the transfer stroke can readily be changed by changing the length of thedrive arm 36 or by extending or shortening the swing .arm members 28. For example, FIG. 7 illustrates how these vswing arms may readily be made of telescoping sections 28 and 28-1 with a screw clamp ferrule 84.

The creasing modules 70 fitinto cut out portions of the table 22 with a circular joint line or seat 90 between the table 22 and the table section 80, the section 80 being included as a part of the creaser module 70. Thus, the creasing module 70 can readily be swung to different angular orientations with respect to the table 22 by turning the table section 80 along the joint line 90 and then securing the creaser module in its new location.

For handling relatively large workpieces W-3 (FIG. 8), for example such as a cloth leg panel of a pair of mens pants, a

' plurality of the transfer modules 26 may conveniently be suitable modified transfer arm means 27A (FIG. 6) for providv ing the'combined translation and rotation includes va bar 63 carrying the resilient vfriction pad 5l and being rotatably mounted on the member 49 by a central pivot 64 having a crank rod 65. A connecting rod 66 is attached `at one end to the crank 65 by adjustable clamps 67 having a pivot between them, and the other end of the rod 66 is secured by another pivot clamp 67 to an adjustable lslide clamp 68 on one of the arms 28..'

As shown in FIG. 6A, by properly positioning the respective clamps 67 and the slide clamp 68, the gripper bar 63 is caused to turn through a change in orientation `of 90 in this case, as the swing arm means 27A move through their advance stroke 53. Other amounts of angular orientation either greater or less than 90*1 can readily be set by adjusting the friction-gripping means 48A. t

In order to provide further flexibility in handling fabric workpieces of various sizes, the registration thereof may be carried out at each of a plurality of work stations. Thus, the

ganged together by attaching them to an overhead mounting. The modules 26 are attached to the mounting 94 by brackets 95 secured to the respective brackets 30 ofthe modules, and a leg 96 ofthe mounting 94 is adjustably secured to the table 22.

v In order to advance the workpiece from the registration station R to the first work station A, the lifting advance cycle Asystem automatically takes care of size change and adjustment of transfer stroke may be eliminated, by the process as shown in FIG. 2C. In stations B, C and D there are registration apparatus 21 and 23 located beneath the table 22 to apply forcel impulses to the fabric directed alternately toward the respective edge stops 24 and 25 so as to impell the edge of the workpiece against the stops. These steps are positioned to locate a predetermined portion of the workpiece in registration for an operation to be performed thereon at the respective station. Thus. the edge portions of the workpiece are properly registered at each of the stations B, C and D for the increments l-2, l-3 and I-4 to be creased in sequence.

The creasing operation at each station is carried out by anY incremental creasing module 70 (FIG.,I) including an upper blade or anvil 7l (FIGS. l0, ll and.12) on anarm 72 having actuating mechanism 73 for moving the anvil blade 7l. Also, there is a lower crimp blade 74 on an arm 75 having actuating mechaniam 76 for moving this blade 74. Normally the blade (FIG. 9B) is used, and the friction gripping means 48B (FIG. 7) include a hollow shoe 100 attached to the member 49. A controlled suction line 101 communicates with the interior of this shoe 100. There are apertures in the bottom surface of the shoe which engages the workpiece. The suction is applied during the pick up, advance, and lowering of the shoe 100.

The lifting advance cycle (FIG. 9B) or the sliding advance cycle (FIG. 9A) may be used in connection with any of the stations whichever may be more convenient in transferring workpieces.

Also, a pickup cycle (FIG. 9B) and suction shoe 100 are used to transfer the workpiece from station D over onto the other workpiece V which has been transferred into the output station 0 from another table 102 as shown in FIG. 1, this table 102 converges with the main table 22 at the output station.

From the foregoing it will be understood that the illustrative embodiments of the process and apparatus of the present invention are well suited to provide the advantages set forth, and since many possible embodiments may be made of the various features of this invention and as the method and apparatus herein described may be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in'a limiting sense and that in certain instances, some of the features of the invention may be used without a corresponding use of other features, all without departing from the scope of the invention as defined by the following claims.

l. A transfer module for transferring fabric workpieces from one station to another station in a production line by sliding the workpieces along a low-friction surface, said transfer module comprising a base, arm means mounted on said base, friction-gripping means carried by said arm means adapted to provide a high friction engagement with workpieces on said surface, said arm means being mounted in movable relationship with respect to said base for motion down'toward said surface and up away therefrom, said arm means also being swingable forward and back generally parallel with said surface, and drive means mounted on said base and moving said arm means from an initial position down toward said surface for engaging said friction-gripping means with a fabric workpiece at said one station, said drive means swinging said arm means in a forward stroke for transferring said workpiece to the other station and moving said arm means up away from said surface for disengaging said friction-gripping means from the workpiece at said other station, and said drive means swinging said arm means back in a return stroke to the initial position in readiness to engage another workpiece at said one station.

2'. A transfer module as claimed in claim 1, and wherein said friction-gripping means are mounted on said arm means for turning movement relative to said arm means, and mechanism for turning said friction-gripping means relative to said arm means as said-arm means are being swung in their forward stroke for providing a predetermined orientation ofthe workpiece as it is being transferred from'one station to another.

3. A transfer module as claimed in claim 2, and wherein said friction-gripping means produce combined translation and rotation of the workpiece as it is being transferred from one station to another. A

4. A transfer module as claimed in claim 1, and wherein said arm means include a parallelogram linkage, said frictionvsubstantially perpendicular to said surface during engagement and disengagement between said friction-gripping means and the workpiece, thereby to prevent accidental lateral displacement ofthe workpiece during said engagement and disengagement at the respective stations.

6. A transfer module as claimed in claim 1, wherein said drive means includes a cam plate connected to said arm means, said cam plate having a contoured slot, a revolving driver element engaging in said contoured slot for swinging said arm means forward and back in the advance and return stroke, and elevator cam means detachably mounted on said base for raising and lowering said driver element to provide the motion of said arm means toward and away from said base.

7. A transfer module as claimed in claim 1, in which said arm means are adjustable in length for adjusting the transfer stroke. 

1. A transfer module for transferring fabric workpieces from one station to another station in a production line by sliding the workpieces along a low-friction surface, said transfer module comprising a base, arm means mounted on said base, frictiongripping means carried by said arm means adapted to provide a high friction engagement with workpieces on said surface, said arm means being mounted in movable relationship with respect to said base for motion down toward said surface and up away therefrom, said arm means also being swingable forward and back generally parallel with said surface, and drive means mounted on said base and moving said arm means from an initial position down toward said surface for engaging said friction-gripping means with a fabric workpiece at said one station, said drive means swinging said arm means in a forward stroke for transferring said workpiece to the other station and moving said arm means up away from said surface for disengaging said friction-gripping means from the workpiece at said other station, and said drive means swinging said arm means back in a return stroke to the initial position in readiness to engage another workpiece at said one station.
 2. A transfer module as claimed in claim 1, and wherein said friction-gripping means are mounted on said arm means for turning movement relative to said arm means, and mechanism for turning said friction-gripping means relative to said arm means as said arm means are being swung in their forward stroke for providing a predetermined orientation of the workpiece as it is being transferred from one station to another.
 3. A transfer module as claimed in claim 2, and wherein said friction-gripping means produce combined translation and rotation of the workpiece as it is being transferred from one station to another.
 4. A transfer module as claimed in claim 1, and wherein said arm means include a parallelogram linkage, said friction-gripping means being controlled by said parallelogram linkage to remain parallel to its initial orientation in spite of the swinging motion of said arm means, thereby to maintain the workpiece in the same orientation as it is transferred from one station to another.
 5. A transfer module as claimed In claim 1, in which said arm means are connected by pivot means to said base for swinging movement toward and away from said surface, said pivot means being located closely adjacent to said surface to provide travel of said friction-gripping means in a direction substantially perpendicular to said surface during engagement and disengagement between said friction-gripping means and the workpiece, thereby to prevent accidental lateral displacement of the workpiece during said engagement and disengagement at the respective stations.
 6. A transfer module as claimed in claim 1, wherein said drive means includes a cam plate connected to said arm means, said cam plate having a contoured slot, a revolving driver element engaging in said contoured slot for swinging said arm means forward and back in the advance and return stroke, and elevator cam means detachably mounted on said base for raising and lowering said driver element to provide the motion of said arm means toward and away from said base.
 7. A transfer module as claimed in claim 1, in which said arm means are adjustable in length for adjusting the transfer stroke. 